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    <title>Document</title>
    <script>
        /* 打印99乘法表 */
        var printStr='';
        for(var i = 1; i <= 9; i++){
            for(var j = 1; j <= i; j++){
                //外部循环几次，内部就循环几次
                printStr += j + 'x' + i + '=' + i * j +'\t';
            }
            printStr +='\n'
        }
        console.log(printStr)
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